On 25/03/2011 16:49, Marc Perkel wrote:
>
> SAV is similar in that it is useful to determine if the sender is coming
> from a bogus email address. I do respect the argument that it creates
> some traffic. But SPF calls also create some traffic as well so if
> you're on the Internet you'll be putting out data to people doing inquires.
>
> There is also an upside to my SAV calls because once I determine an IP
> needs to be blacklisted then I no longer make the SAV call and those who
> use my blacklist stop making SAV calls as well causing a reduction in
> traffic.
>
> So - SAV is a lightweight call and I use it and it works.
>
> For what it's worth - the best way not to have your domain spoofed is to
> support SAV calls and not have a wildcard account. Spammers tend to
> spoof domains where the validity of the sender can not be determined.
There are two main issues with SAV. Firstly, the majority of spam comes
from forged, rather than non-existent, addresses, and hence verifying
those addresses with SAV is not only useless as an anti-spam method but
is also a form of backscatter. And, secondly, large volumes of
verification probes are indistinguishable from a dictionary attack and
hence are likely to get your server blacklisted.
Mark
--
http://mark.goodge.co.uk
http://www.ratemysupermarket.com
